diff --git a/tests/unit/proxy/_experimental/mcp_server/test_discoverable_endpoints.py b/tests/unit/proxy/_experimental/mcp_server/test_discoverable_endpoints.py
index 8a0352e82a1..0736391642b 100644
--- a/tests/unit/proxy/_experimental/mcp_server/test_discoverable_endpoints.py
+++ b/tests/unit/proxy/_experimental/mcp_server/test_discoverable_endpoints.py
@@ -15,8 +15,11 @@ from litellm.proxy._types import LiteLLM_MCPServerTable
 from litellm.types.mcp import MCPAuth
 
 if TYPE_CHECKING:
+    from collections.abc import Iterator
+
     import httpx
     from cryptography.hazmat.primitives.asymmetric.rsa import RSAPrivateKey
+    from fastapi import APIRouter
 
     from litellm.proxy.auth.handle_jwt import JWTHandler
 
@@ -11903,52 +11906,46 @@ def test_named_resource_discovery_follows_matching_authorization_issuer(
     assert authorization.json()["issuer"] == resource["authorization_servers"][0]
 
 
-def test_static_root_path_authorization_discovery_preserves_issuer(monkeypatch, tmp_path):
-    import subprocess
-    import sys
+@pytest.fixture
+def _gateway_root_path_discovery_router(monkeypatch: pytest.MonkeyPatch) -> "Iterator[APIRouter]":
+    """The ``.well-known`` routes bake ``SERVER_ROOT_PATH`` into their paths when the module is
+    executed, so it is re-executed under the gateway env and its namespace restored afterwards
+    (a second reload would hand earlier importers a different ``router`` object)."""
+    import importlib
 
+    from litellm.proxy._experimental.mcp_server import discoverable_endpoints
+
+    snapshot: Final = dict(vars(discoverable_endpoints))
     monkeypatch.setenv("SERVER_ROOT_PATH", "/gateway")
-    monkeypatch.setenv("PROXY_BASE_URL", "http://testserver/gateway")
-    monkeypatch.setenv("LITELLM_UI_PATH", str(tmp_path / "ui"))
-    result = subprocess.run(
-        [
-            sys.executable,
-            "-c",
-            """
-import json
-from fastapi import FastAPI
-from fastapi.testclient import TestClient
-from litellm.proxy._experimental.mcp_server.discoverable_endpoints import router
-from litellm.proxy._experimental.mcp_server.mcp_server_manager import global_mcp_server_manager
-from litellm.types.mcp import MCPAuth, MCPTransport
-from litellm.types.mcp_server.mcp_server_manager import MCPServer
+    monkeypatch.setenv("PROXY_BASE_URL", "https://llm.example.test/gateway")
+    try:
+        yield importlib.reload(discoverable_endpoints).router
+    finally:
+        added_keys: Final = [key for key in vars(discoverable_endpoints) if key not in snapshot]
+        for key in added_keys:
+            delattr(discoverable_endpoints, key)
+        vars(discoverable_endpoints).update(snapshot)
 
-global_mcp_server_manager.registry['example'] = MCPServer(
-    server_id='example', name='example', server_name='example', alias='example',
-    transport=MCPTransport.http, auth_type=MCPAuth.oauth2,
-    authorization_url='https://idp.example.com/authorize', token_url='https://idp.example.com/token',
-)
-app = FastAPI(root_path='/gateway')
-app.include_router(router)
-with TestClient(app) as client:
-    responses = {
-        path: client.get('/.well-known/oauth-authorization-server/gateway/' + path)
-        for path in ('mcp/example', 'example/mcp', 'example', 'mcp')
-    }
-    print(json.dumps({path: {'status': response.status_code, 'body': response.json()}
-                      for path, response in responses.items()}))
-""",
-        ],
-        capture_output=True,
-        text=True,
-        check=True,
-        timeout=60,
-    )
-    responses = json.loads(result.stdout)
-    for path in ("mcp/example", "example/mcp", "example", "mcp"):
-        assert responses[path]["status"] == 200, responses[path]
-        assert responses[path]["body"]["issuer"] == f"http://testserver/gateway/{path}"
-    assert responses["example/mcp"]["body"]["token_endpoint"] == "http://testserver/gateway/example/token"
+
+def test_static_root_path_authorization_discovery_preserves_issuer(
+    _gateway_root_path_discovery_router: "APIRouter", _isolated_mcp_registry: "dict[str, MCPServer]"
+) -> None:
+    from fastapi import FastAPI
+    from fastapi.testclient import TestClient
+
+    server: Final = _create_oauth2_server(server_id="example", name="example", server_name="example", alias="example")
+    _isolated_mcp_registry[server.server_id] = server  # rebind-ok: the fixture hands the test an empty registry to fill
+    app: Final = FastAPI(root_path="/gateway")
+    app.include_router(_gateway_root_path_discovery_router)
+    with TestClient(app) as client:
+        responses: Final = {
+            path: client.get(f"/.well-known/oauth-authorization-server/gateway/{path}")
+            for path in ("mcp/example", "example/mcp", "example", "mcp")
+        }
+    for path, response in responses.items():
+        assert response.status_code == 200, response.text
+        assert response.json()["issuer"] == f"https://llm.example.test/gateway/{path}"
+    assert responses["example/mcp"].json()["token_endpoint"] == "https://llm.example.test/gateway/example/token"
 
 
 @pytest.fixture